This invention relates to patient interfaces particularly though not solely for use in delivering CPAP therapy to patients suffering from obstructive sleep apnoea (OSA).
In the art of respiration devices, there are well known variety of respiratory masks which cover the nose and/or mouth of a human user in order to provide a continuous seal around the nasal and/or oral areas of the face such that gas may be provided at positive pressure within the mask for consumption by the user. The uses for such masks range from high altitude breathing (i.e., aviation applications) to mining and fire fighting applications, to various medical diagnostic and therapeutic applications.
One requisite of such respiratory masks has been that they provide an effective seal against the user""s face to prevent leakage of the gas being supplied. Commonly, in prior mask configurations, a good mask-to-face seal has been attained in many instances only with considerable discomfort for the user. This problem is most crucial in those applications, especially medical applications, which require the user to wear such a mask continuously for hours or perhaps even days. In such situations, the user will not tolerate the mask for long durations and optimum therapeutic or diagnostic objectives thus will not be achieved, or will be achieved with great difficulty and considerable user discomfort.
U.S. Pat. Nos. 5,243,971 and U.S. Pat. No. 6,112,746 are examples of prior art attempts to improve the mask system. U.S. Pat. No. 5,570,689 and PCT publication No. WO 00/78384, and U.S. Pat. No. 6,119,693 are examples of attempts to improve the forehead rest.
It is an object of the present invention to attempt to provide a patient interface which goes some way to overcoming the abovementioned disadvantages in the prior art or which will at least provide the industry with a useful choice.
Accordingly in one aspect the present invention may broadly be said to consist in a device for delivering a supply of gases to a user comprising:
a patient interface, in use in fluid communication with said supply of gases,
a forehead rest engaging said interface including a deformable resilient member configured to in Use rest against the face of a user, said deformable resilient member including curved portion and a section curved portion.
Preferably said deformable resilient member is configured to provide at least a first mode of deformation and a second mode of deformation, where in the force required to deform in said first mode is less than that required to deform in said second mode.
Preferably said deformable resilient member includes a load bearing surface is adapted to provide a substantially even deforming force.
Preferably said first mode of deformation comprises said first curved portion deforming and said second mode of deformation comprises the composite deforming of said first curved portion and said second curved portion.
Preferably said second curved portion is nested within, and similar to cross sectional shape to said first curved portion.
Preferably said second curved member is smaller in cross section than said first curved member and either or both are attached at each end to a base member.
Preferably a first curved portion is attached at both ends to a base member and said second curved portion is inverted and attached at each end to, and smaller in height than, said first curved member; said second mode of deformation begins where said second bridge member is in contact with said base member and both said first bridge member and said second bridge member simultaneously deform.
Preferably said first bridge further comprises further members attaching to the said curved section at least three points to form an outer cross section substantially quadrilateral in cross section.
Preferably said resilient deformable member is moulded from silicon.
Preferably said resilient deformable member is extruded from silicon.
To those skilled in the art to which the invention relates, many changes in construction and widely differing embodiments and applications of the invention will suggest themselves without departing from the scope of the invention as defined in the appended claims. The disclosures and the descriptions herein are purely illustrative and are not intended to be in any sense limiting.
The invention consists in the foregoing and also envisages constructions of which the following gives examples.